The process of diagnosing an illness or a disease typically involves recording the demographic information about the patient and documenting the findings that the patient is exhibiting. Together the demographic information and the finding information provide a patient profile. The diagnosing physician can compare the demographic information and the finding information of the patient against a listing of the common and descriptive findings for a particular disease, and can determine the likelihood that such a disease would be present in a patient having the information set forth in the profile.
For this process to work well, the physician must be provided with a database of information that sets forth the descriptive symptoms for a particular disease. Unfortunately, this information is difficult to come by. Frequently, the doctor must rely on personal experience, or search through the literature to identify studies that set forth statistical ranges indicating the likelihood that a particular finding is present in a patient with a particular disease. Often, however, the literature only offers general qualitative discussions as to the frequency or relevancy of a particular finding for a particular disease. Such qualitative expressions include statements that a particular disease is "very frequently" accompanied by a particular finding or that the finding is "almost never absent" in a patient with a particular disease. Similar qualitative expressions are used to describe the likelihood that a patient with a certain demographic profile will have a particular disease.
Although qualitative expressions provide information as to the probability that a particular finding will be seen in a patient suffering from a particular disease, the information is conveyed in a somewhat ambiguous manner and lacks the precision of a numerical statement that typically would be provided by a rigorous statistical analysis. However, patient studies that result in rigorous statistical analysis are few and far between. The scarcity of such publications arises in part from the difficulty in obtaining research support for analyzing a sufficiently large pool of candidates to come away with meaningful statistical data. Consequently, much of the diagnostic information available to a treating physician is in the form of qualitative expressions.
Accordingly, there is a need in the art for a system that can extract reliable and meaningful information from qualitative expressions.